Anthocyanin phytochemical profiles and anti-oxidant activities of Vitis candicans and Vitis doaniana

Polyphenol supplementation boosts aerobic endurance in athletes: systematic review

In recent years, an increasing trend has been observed in the consumption of specific polyphenols, such as flavonoids and phenolic acids, derived from green tea, berries, and other similar sources. These compounds are believed to alleviate oxidative stress and inflammation resulting from exercise, potentially enhancing athletic performance. This systematic review critically examines the role of polyphenol supplementation in improving aerobic endurance among athletes and individuals with regular exercise habits. The review involved a thorough search of major literature databases, including PubMed, Web of Science, SCOPUS, SPORTDiscus, and Embase, covering re-search up to the year 2023. Out of 491 initially identified articles, 11 met the strict inclusion criteria for this review. These studies specifically focused on the incorporation of polyphenols or polyphenol-containing complexes in their experimental design, assessing their impact on aerobic endurance. The methodology adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the risk of bias was evaluated using the Cochrane bias risk assessment tool. While this review suggests that polyphenol supplementation might enhance certain aspects of aerobic endurance and promote fat oxidation, it is important to interpret these findings with caution, considering the limited number of studies available. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023453321.

Effects of montmorency tart cherry (L. Prunus Cerasus) consumption on nitric oxide biomarkers and exercise performance

The purpose of this study was to investigate the effects of Montmorency tart cherry juice (MC) on nitric oxide (NO) biomarkers, vascular function, and exercise performance. In a randomized, double-blind, placebo (PLA)-controlled, crossover study, 10 trained cyclists (mean ± SD; V˙O_2peak 59.0 ± 7.0 mL/kg/min) acutely ingested 30 mL of either MC or PLA following dietary restrictions of polyphenol-rich compounds and completed 6-minutes moderate- and severe-intensity cycling bouts 1.5 hour post-ingestion on 2 occasions for each experimental condition. The severe-intensity cycling test was continued to exhaustion on 1 occasion and immediately followed by a 60-seconds all-out sprint on the other occasion. Blood pressure, pulse wave measures, tissue oxygenation index, and plasma nitrite concentration were assessed pre- and 1.5 hour post-ingestion. Time to exhaustion was not different between conditions (P > .05), but peak power over the first 20 seconds (363 ± 42 vs 330 ± 26 W) and total work completed during the 60-seconds all-out sprint (21 ± 3 vs 19 ± 3 kJ) were 10% higher in the MC trial compared to the PLA trial (P < .05). Systolic blood pressure was 5 ± 2 mm Hg lower 1.5 hour post-MC supplementation compared to PLA supplementation (P < .05). There were no differences in pulse wave measures, plasma nitrite concentration, or tissue oxygenation between the MC and PLA trials (P > .05). These results suggest that acute supplementation with MC can lower blood pressure and improve some aspects of exercise performance, specifically end-sprint performance, in trained cyclists.

Effect of New Zealand Blackcurrant Extract on Performance during the Running Based Anaerobic Sprint Test in Trained Youth and Recreationally Active Male Football Players

It was observed previously that New Zealand blackcurrant (NZBC) extract reduced slowing of the maximal 15 m sprint speed during the Loughborough Intermittent Shuttle Test. We examined the effect of NZBC extract on the performance of the Running Based Anaerobic Sprint Test (RAST, 6 × 35-m sprints with 10 seconds passive recovery) in trained youth and recreationally active football players. Fifteen recreationally active (University team) (age: 20 ± 1 years, height: 174 ± 19 cm, body mass: 80 ± 13 kg) and nine trained youth players (English professional club) (age: 17 ± 0 years, height: 178 ± 8 cm, body mass: 69 ± 9 kg, mean ± SD) participated in three testing sessions. Prior to the RASTs, participants consumed two capsules of NZBC extract (600 mg∙day⁻¹ CurraNZ^®) or placebo (P) for 7 days (double blind, randomised, cross-over design, wash-out at least 14 days). Ability difference between groups was shown by sprint 1 time. In the placebo condition, trained youth players had faster times for sprint 1 (5.00 ± 0.05 s) than recreationally active players (5.42 ± 0.08 s) (p < 0.01). In trained youth players, there was a trend for an effect of NZBC extract (p = 0.10) on the slowing of the sprint 1 time. NZBC extract reduced slowing of the sprint 5 time (P: 0.56 ± 0.22 s; NZBC: 0.35 ± 0.25, p = 0.02) and this was not observed in recreationally active players (P: 0.57 ± 0.48 s; NZBC: 0.56 ± 0.33, p = 0.90). For fatigue index, expressed as a % change in fastest sprint time, there was a strong trend to be lower in both trained youth and recreationally active players combined by NZBC extract (P: −13 ± 7%; NZBC: −11 ± 6%, p = 0.06) with 12 participants (five trained youth) experiencing less fatigue. New Zealand blackcurrant extract seems to benefit repeated sprint performance only in trained football players.

Effect of New Zealand Blackcurrant Extract on Repeated Cycling Time Trial Performance

New Zealand blackcurrant (NZBC) extract increased 16.1 km cycling time trial performance. The aim of the present study was to examine the effect of NZBC extract on 2 × 4 km time trial performance. Ten male cyclists (age: 30 ± 12 years, body mass: 74 ± 9 kg, height: 179 ± 7 cm, body fat: 11 ± 3%, V˙O_2max: 55 ± 7 mL·kg⁻¹·min⁻¹, mean ± SD) volunteered. Participants were familiarized with the time trials. Participants consumed capsulated NZBC extract (300 mg·day⁻¹ CurraNZ™; containing 105 mg anthocyanin) or placebo for seven days (double blind, randomised, cross-over design, wash-out at least seven days) before 2 × 4 km time trials (10 min active self-paced recovery between trials) (SRM ergometer, SRM International, Germany). Heart rate was recorded and blood lactate sampled immediately after each trial and 8 min into recovery between the trials. Times over comparable one km distances in each 4 km time trial were similar. No effect was observed for the time to complete the first (placebo: 380 ± 28 s, NZBC: 377 ± 27 s) and second 4 km of cycling (placebo: 391 ± 32 s, NZBC: 387 ± 30 s), within both groups the second 4 km times slower by 11 ± 8 s and 11 ± 9 s for placebo and NZBC, respectively. However, the total time of the two 4 km cycling trials was 0.82% faster with NZBC extract (placebo: 771 ± 60 s, NZBC 764 ± 56 s, p = 0.034) with seven participants having faster total times. There was no effect of NZBC on heart rate and lactate values at identical time points. New Zealand blackcurrant extract seems to be beneficial in repeated short-distance cycling time trials for overall performance.

Beneficial Effects of New Zealand Blackcurrant Extract on Maximal Sprint Speed during the Loughborough Intermittent Shuttle Test

New Zealand blackcurrant (NZBC) extract has been shown to enhance high-intensity intermittent treadmill running. We examined the effects of NZBC extract during the Loughborough Intermittent Shuttle Test (LIST) which involves 5 × 15 min blocks with intermittent 15-m maximal sprints, interspersed by moderate and high-intensity running to simulate team sport activity, and a subsequent run to exhaustion. Thirteen males (age: 22 ± 1 year, V˙O2max: 50 ± 5 mL·kg⁻¹·min⁻¹) participated in three indoor sessions (T: 24 ± 3 °C, humidity: 52% ± 9%). In the first session, a multistage fitness test was completed to determine peak running speed and estimate V˙O2max. Participants consumed NZBC extract in capsules (300 mg·day⁻¹ CurraNZ™) or placebo (PL) (300 mg·day⁻¹ microcrystalline cellulose M102) for seven days in a double-blind, randomized, cross-over design (wash-out at least seven days). NZBC extract did not affect average 15-m sprint times in each block. NZBC reduced slowing of the fastest sprint between block 1 and 5 (PL: 0.12 ± 0.07 s; NZBC: 0.06 ± 0.12 s; p < 0.05). NZBC extract had no effect on heart rate, vertical jump power, lactate and time to exhaustion (PL: 13.44 ± 8.09 min, NZBC: 15.78 ± 9.40 min, p > 0.05). However, eight participants had higher running times to exhaustion when consuming NZBC extract. New Zealand blackcurrant extract may enhance performance in team sports with repeated maximal sprints.

Grape skin extracts from winemaking by-products as a source of trapping agents for reactive carbonyl species

BACKGROUND

Clinical evidence supports the relationship between carbonyl stress and type II diabetes and its related pathologies. Methylglyoxal (MGO) is the major dicarbonyl compound involved in carbonyl stress. Efforts are therefore being made to find dietary compounds from natural sources that could exert an MGO trapping response.

RESULTS

The in vitro MGO trapping capacity of six red and seven white grape skin extracts (GSE) obtained from winemaking by-products was investigated. Methanolic GSE exhibited a promising MGO trapping capacity that was higher in red GSE (IC50 2.8 mg mL(-1)) when compared with white GSE (IC50 3.2 mg mL(-1)). The trapping ability for red GSE correlated significantly with total phenolic content and antioxidant capacity. However, no correlations were observed for white GSE, which suggests that other compounds were involved in the trapping activity.

CONCLUSION

GSE may be considered a natural source of carbonyl stress inhibitors, thus opening up its possible utilization as a nutraceutical ingredient. Further investigations are required to understand the mechanism involved in the carbonyl trapping ability of red and white grape skin samples and their relationship with glycation.

Highly efficient extraction of anthocyanins from grape skin using deep eutectic solvents as green and tunable media

Deep eutectic solvents (DESs) were investigated as tunable, environmentally benign, yet superior extraction media to enhance the extraction of anthocyanins from grape skin, which is usually discarded as waste. Ten DESs containing choline chloride as hydrogen bond acceptor combined with different hydrogen bond donors were screened for high extraction efficiencies based on the anthocyanin extraction yields. As a result, citric acid, D-(+)-maltose, and fructose were selected as the effective DES components, and the newly designed DES, CM-6 that is composed of citric acid and D-(+)-maltose at 4:1 molar ratio, exhibited significantly higher levels of anthocyanin extraction yields than conventional extraction solvents such as 80% aqueous methanol. The final extraction method was established based on the ultrasound-assisted extraction under conditions optimized using response surface methodology. Its extraction yields were double or even higher than those of conventional methods that are time-consuming and use volatile organic solvents. Our method is truly a green method for anthocyanin extraction with great extraction efficiency using a minimal amount of time and solvent. Moreover, this study suggested that grape skin, the by-products of grape juice processing, could serve as a valuable source for safe, natural colorants or antioxidants by use of the eco-friendly extraction solvent, CM-6.

New Zealand blackcurrant extract improves cycling performance and fat oxidation in cyclists

PURPOSE

Blackcurrant intake increases peripheral blood flow in humans, potentially by anthocyanin-induced vasodilation which may affect substrate delivery and exercise performance. We examined the effects of New Zealand blackcurrant (NZBC) extract on substrate oxidation, cycling time-trial performance and plasma lactate responses following the time-trial in trained cyclists.

METHODS

Using a randomized, double-blind, crossover design, 14 healthy men (age: 38 ± 13 years, height: 178 ± 4 cm, body mass: 77 ± 9 kg, VO2max: 53 ± 6 mL kg(-1) min(-1), mean ± SD) ingested NZBC extract (300 mg day(-1) CurraNZ™ containing 105 mg anthocyanin) or placebo (PL, 300 mg microcrystalline cellulose M102) for 7 days (washout 14 days). On day 7, participants performed 30 min of cycling (3 × 10 min at 45, 55 and 65 % VO2max), followed by a 16.1 km time-trial with lactate sampling during a 20-min passive recovery.

RESULTS

NZBC extract increased fat oxidation at 65 % VO2max by 27 % (P < 0.05) and improved 16.1 km time-trial performance by 2.4 % (NZBC: 1678 ± 108 s, PL: 1722 ± 131 s, P < 0.05). Plasma lactate was higher with NZBC extract immediately following the time-trial (NZBC: 7.06 ± 1.73 mmol L(-1), PL: 5.92 ± 1.58 mmol L(-1), P < 0.01).

CONCLUSIONS

Seven-day intake of New Zealand blackcurrant extract improves 16.1 km cycling time-trial performance and increases fat oxidation during moderate intensity cycling.

Free Radical Scavenging Properties of Skin and Pulp Extracts of Different Grape Cultivars In Vitro and Attenuation of H2O2-Induced Oxidative Stress in Liver Tissue Ex Vivo

Grapes are the richest source of antioxidants due to the presence of potent bioactive phytochemicals. In this study, the phytochemical contents, scavenging activities and protective role against H2O2-induced oxidative stress in liver tissue ex vivo of four grape (Vitis vinifera) cultivars extracts, namely Flame seedless (black), Kishmish chorni (black with reddish brown), Red globe (red) and Thompson seedless mutant (green), were evaluated. The total phenolics and flavonoids content in pulp or skin fractions of different grape cultivars were in the range of 47.6-310 mg gallic acid equivalent/g fresh weight (fw), and 46.6-733.3 µg catechin equivalent/g fw respectively. The scavenging activities in skin of different grape varieties against 2,2-diphenyl-1-picrylhydrazyl (44-58 %), hydrogen peroxide (15.3-18.6 %), and hydroxyl radicals (50-85 %), were higher than pulp of the corresponding cultivars. These scavenging activities of grape extracts were found to be significantly (p < 0.01) correlated with the levels of total phenols, flavonoids and ascorbic acid. Liver tissues from goat treated with H2O2 (500 μM) showed significantly decreased GSH content by 42.9 % and activities of catalase by 50 % and glutathione reductase by 66.6 %; while increased thiobarbituric acid reactive substances and nitric oxide level by 2.53- and 0.86-fold, respectively, and activity of glutathione S-transferase by 0.96-fold. Grape skin extracts showed the stronger protective activity against H2O2-induced oxidative stress in liver tissue ex vivo, than its pulp of any cultivar; and the Flame seedless (black) cultivar showed the highest potential. In conclusion, our study suggested that the higher antioxidant potential, phytochemical contents and significant scavenging capacities in pulp and skin of grape extracts showed the protective action of grape extracts against H2O2-induced oxidative stress in liver tissue ex vivo.